nuttx/arch/arm/src/armv7-a/arm_restorefpu.S
2016-04-18 06:50:45 -06:00

105 lines
3.8 KiB
ArmAsm

/************************************************************************************
* arch/arm/src/armv7-a/arm_restorefpu.S
*
* Copyright (C) 2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
************************************************************************************/
/************************************************************************************
* Included Files
************************************************************************************/
#include <nuttx/config.h>
#include <arch/irq.h>
#ifdef CONFIG_ARCH_FPU
.file "arm_restorefpu.S"
/************************************************************************************
* Public Symbols
************************************************************************************/
.globl up_restorefpu
/************************************************************************************
* Public Functions
************************************************************************************/
.text
/************************************************************************************
* Name: up_restorefpu
*
* Description:
* Given the pointer to a register save area (in R0), restore the state of the
* floating point registers.
*
* C Function Prototype:
* void up_restorefpu(const uint32_t *regs);
*
* Input Parameters:
* regs - A pointer to the register save area containing the floating point
* registers.
*
* Returned Value:
* This function does not return anything explicitly. However, it is called from
* interrupt level assembly logic that assumes that r0 is preserved.
*
************************************************************************************/
.globl up_restorefpu
.type up_restorefpu, function
up_restorefpu:
add r1, r0, #(4*REG_S0) /* R1=Address of FP register storage */
/* Load all floating point registers. Registers are loaded in numeric order,
* s0, s1, ... in increasing address order.
*/
vldmia r1!, {s0-s31} /* Restore the full FP context */
/* Load the floating point control and status register. At the end of the
* vstmia, r1 will point to the FPCSR storage location.
*/
ldr r2, [r1], #4 /* Fetch the floating point control and status register */
vmsr fpscr, r2 /* Restore the FPCSR */
bx lr
.size up_restorefpu, .-up_restorefpu
#endif /* CONFIG_ARCH_FPU */
.end